Seam for joining the meeting or overlapping edge portions of fabric sections



April 29, 1952. F LUTZ 2,595,152

SEAM FOR JOINING TI-IE MEETING OR OVERLAPPING EDGE PORTIONS OF FABRICSECTIONS Filed Oct 6, 1950 4 Sheets-Sheet l 4 6 J 1151. Z 7 w 6 a 5 II J6/) .5 J IE3. E?- E2 I 1 I| a I:

3 N H a a 5 E 1 ll 1 I I 3 J 5 1 4 r; 'fl 9 53-77 W I a INVENTOR Friedrz'cfi Luiz ATTORNEYS April 29, 1952 F. LUTZ 2,595,152

. SEAM FOR JOINING THE MEETING OR OVERLAPPING EDGE PORTIONS 0F FABRICSECTIONS Filed Oct. 6, 1950 4 Sheets-Sheet 2 J 5 I1EE 2 7 g a a J J INVENTOR m, Mm

ATTORNEYS April 29, 1952 Filed Oct. 6, 1950 J6 J 6 J J UTZ 2,595,152

F. L SEAM FOR JOINING THE MEETING OR OVERLAPPING EDGE PORTIONS OF FABRICSECTIONS 4 Sheets-Sheet 3 INVENTOR 17" i eJrz'cA L a i2:

MWM MAM ATTORNEY April 29, 1952 F LUTZ 2,595,152

SEAM FOR JOINING TEE MEETING OR OVERLAPPING EDGE PORTIONS OF FABRICSECTIONS Filed 001;. 6, 1950 4 Sheets-Sheet 4 1N VENT OR frzearz 'c& in22 3km my] ATTORNEYS Patented Apr. 29, '1952 SEAM FOR JOINING THEMEETING OR OVERLAPPING EDGE PORTIONS OF FABRIC SECTIONS Friedrich Lutz,Stuttgart, Germany, assignor to Union Special Maschinenfabrik, G. in. b.H., Stuttgart, Wurttemberg, Germany Application October 6, 1950, SerialNo. 188,716 In Germany May 12, 1950 Claims. 1

The invention relates 'to new and useful im provements in a seam forsewed articles and more particularly a flat seam for joining the meetingor overlapping edge portions of opposed fabric sections. a

Flat seams of the above type when used for joining the edge portions ofgarments have to meet high requirements as to elasticity in a directionlongitudinally of the seam and non-elasticity in a transverse direction.Furthermore, the seam should sufliciently cover the underface of thefabric sections being joined without undue thickness and should be safeagainst raveling in case of the breaking of a thread or threads.

The present known seams of the above type are generally somewhat elasticin a longitudinal direction of the seam but they are also elastic in atransverse direction. When these known seams are used for joining themeeting edges of fabric sections, particularly if no cover thread isused, the edges under transverse stress will separate and produce anobjectionable gapping.

Efforts have been made to decrease the transverse elasticity of the seamby using relatively large size looper threads. This results in thethickening of the lower side of the seam and such thickening is subjectto increased wear and tear due to rubbing, particularly when thegarments are washed. These known seams are safe against raveling to onlya limited extent when a seam breaks.

The seam, according to the present invention, avoids the objectivedisadvantages entirely and sufficiently fulfills the previouslymentioned requirements to be met by such seam.

The several embodiments of the new seam illustrated are very elastic ina longitudinal direction while they are particularly non-elastic in atransverse' direction. The new seams sufficiently cover the meeting edgeportions of the fabric sections without increased thickness and the newseam is safe against raveling if the seam should break.

A characteristic feature of the seams embodying the invention is thatall of its needle thread loops are engaged by only one looperoscillating transversely with respect to the sewing direction. The loopsof the looper thread are not locked by engagement of the needle threadloops of the subsequent stitches but are locked by a thread carryinglooper moving across the path of the first looper and passing a looperthread loop through the first-named looper thread loop as it emergesfrom the needle thread loops. The loops of this second looper thread areengaged by the needles of the following stitch and locked by theirthread loops. v 1

In the drawings, the fabric sections have been omitted for the sake ofclearness and only the needle threads and looper threads and theirrespective loops and the concatenation of the loops embodying thepresent invention are shown.

Figure 1 is a perspective view showing the improved seam as embodyingtwo needle threads and two looper threads, one of the looper -threadsbeing formed into loops for locking the opposed needle loops and theother looper thread being formed into loops for lockingthe first namedlooper thread loops, said second looper thread loops being in turnlocked by the needle thread loops.

Figure 2 is a view similar to Figure 3, but showing three needle threadsformed into loops wherein all three needle loops are locked by a singlelooper thread loop.

Figure 2 is a view of the underside of the completed seam showing thefabric sections lapped within the concatenated stitching threads.

Figure 3 is a View similar to Figure 1, but showing four needle threadswherein the loops of all four threads are secured by a single looperthread.

Figure 4 is a view similar to Figure 2 but showing a covering threadplaced about the needle thread loops on the upper face of the fabricsections.

Figure 5 is a view similar to Figure 2, but showing a third looperthread which is passed through the needle thread loop adjacent themiddle thread loop and locked by a needle loop of the next succeedingstitch.

Figure 6 is a view similar to Figure 5, but showing four needle threadsand three looper threads arranged and concatenated as shown in Figure 5.

Figure '7 is a view showing a modified form of the seam wherein thesecond looper thread, which is formed into loops passing through thefirst looper thread for locking the same, is expanded and secured byboth needle thread loops of the next succeeding stitch.

Figure 8 is a view similar to Figure 7 wherein three needles are usedand the second looper thread loop is expanded and locked by all threeneedle thread loops.

Referring to Figure l of the drawings the improved seam is made by twoneedles set abreast. The needle threads I and 2 of the needles areformed into loops 3 and 4 respectively, which loops are opposed toeachother. This seam may be used for joining abutted edges of fabric inwhich case the abutted edges would lie midway between the lines ofneedle thread loops. It may also be used for joining the lapped edgeportions of fabric sections wherein the sections are lapped withinthe'limits of the seam, that is,

3 the lapped sections lie between the needle thread loops. The needlethread loops 3 and 4 are locked by a looper carrying a looper thread 5.The looper passes through first the needle thread loop 3 and then theneedle thread loop 4.

The looper thread loop is indicated at 6 and the two strands of the looplie close beside each other and extend transversely of the edge portionsof the fabric sections and substantiallyat right angles to the meetingedges of the fab ric sections. This looper thread loop 6 is locked notby the succeeding needle loops, but by a second looper thread 1 formedinto loops 8, 8. The looper carrying the looper thread I crosses thepath of the first looper at a place close to the needle forming theneedle thread loops 4. The looper thread 8 passes through the looperthread very close to the needle thread loop 4 and extends transverselyacross the fabric sections and is locked by the needle thread loop 3 ofthe next succeeding stitch. The strands of this looper thread aresubstantially close together and the loop while it is slanting withrespect to the longitudinal direction still it is very much more nearlythe transverse direction of the seam.

The sequence of looper threads transverse and/or slanting with respectto the longitudinal direction of the seam is obtained in the mannerabove described. These looper thread loops are adapted toopen similarlyas the bellows of an accordion when tension is exerted in thelongitudinal direction of the seam. This is the basis for highelasticity of the new seam not obtained by any of the present knownmeans. In the known seams the looper threads are expanded so as to beinterlocked by both the needle thread loops of the next succeedingstitch, and are in general substantially parallel with respect to thelongitudinal direction of the seam. Thus when tension is exerted in thelongitudinal direction of the se'amarather limited number of stretchablethreadloops are available and the number of such loops stretchable in atransverse direction is'greater to the same extent. This explainsthe'high degree'of undesired transverse elasticity in the known seamswhich is absolutely avoided in applicants new seam, because in said newscam the loops of the threads of the loopers which are transverse to thedirection of the seam are substantially stretched so that they cannot beexpanded.

This is particularly true since the two strands of the thread loops ofthe transversely operating looper as well-as the strands of the secondlooper thread loops are close together and oppose any transverse stretchwith increased resistance.

It is noted that the two strands of the loop of the first looper act ina similar manner to the upper cover thread used in some of the fiatseams. This upper cover thread is used in part to cover the upper faceof the fabric and in particular to laterally hold together the abuttededges of the seam, that is, the upper cover thread opposes thetransverse elasticity and consequently it can be easily seen thatpractically no transverse elasticity is present in the new seam if theupper cover thread is omitted.

In Figure '2 of the drawings, there is shown a three needle seam. Inaddition to the needle threads I and 2 withtheir loops3 and 4, a thirdneedle thread 9 is employed. This needle thread 9 is formed into threadloops H). The loops lie in a line parallel with the-needle thread loops3 and 4 and each needle thread loop it also ill lies in a line at rightangles to the center line of the seam. The looper thread 5 is formedinto loops 6 which pass transversely through all three needle threadloops 3, 4 and H]. The looper thread loop 6 is locked by the looperthread '1 formed into loops 8 in the same manner as described inconnection with Figure 1. The looper thread loop 8 does not engage inany way the needle thread loop 19 but passes between succeeding needlethread loops l0 and is locked by the needle thread loop 3. As noted,this seam is particularly adapted for the joining of fabric sectionswhere the edge portions are lapped within the limits of the seam. InFigure 2 there is a bottom plan view of this seam shown. One of thefabric sections is indicated at A and its edge at a. The other fabricsection is indicated at B and its edge in broken lines at b. In suchcase the needle thread loops ill will pass through the lapped portionsof the fabric sections. This seam, for reasons stated above. isunusually elastic in a direction longitudinally of the seam and it isunusually non-elastic in a direction transversely of the seam.

In Figure 4, the arrangements of the needle thread loops'and the looperthread loops is the same as in Figure 2. In this figure of thedrawingthere is shown a covering thread II which lies on the upper face of thejoined fabric sections. This covering thread is formed by a threadcarrying member moving transversely of the seam. The thread is laid backand forth across the seam so as to encircle the needle thread loops inthe outer rows of loops. This is a usual form of covering thread.

In Figure 3 the improved method of locking the needle thread loops isshown as applied to the four needle stitch. There is a needle thread Iand a needle thread 2 formed respectively into needle thread loops 3 and4. These needle thread loops 3 and 4 lie in parallel rows at the outerlimits of the seam. In between the needles'carrying the threads I and 2are needles carrying needle threads I 2 and 13. The needle'thread I2 isformed into loops l4 and the needle thread [3 is formed into loops I5.The needle thread loops l4 and I5 lie betweenthe rows of needle threadloops 3 and 4. They areparallel with each other and also parallel withthe outer rows of needle thread loops. When this seam is used foruniting fabric sections then the edges will be abutted between the rowsof needle thread loops M'and IS. The needle thread loops are lockedby .asingle looper thread 5 formed into loops 6 extending transversely acrossthe seam and through all four of the needle thread'loops that'areopposed to each other. The looper thread 6 is locked by a looper thread1 which is formedinto loops 8. The loop 8 passes through the looperthread loop 6 immediately after it emerges from the needle thread loop4. This loop 8 extends transversely across the seam andis locked by theneedle thread loop 3 at the opposite sideof the seam. It will be notedthat the same arrangement of looper thread loops and theirconcatenationwith each other and the needle thread loops are the same inprinciple asshown in connection with the two needle seam in Figure 1 and also thethree needle seam in Figure 4.

In Figure 5 there is shown aseam similar to the seam shown in Figure -2.That is, it is a three needle seam. All of the needle loops are lockedby a single looper thread loop. There are. however, two looper threadsformed :into loops for giving more thorough coverage and simultaneouslytherewith .a higher elasticity. The needle threads I, 9 and 2 are formedinto needle loops 3, l and 4 respectively. These needle thread loops onthe underface of the fabric are all locked by a single looper threadloop 6, the same as in Figure 2. The looper thread 1 is formed into aloop l6 which passes through the loop 6 as it emerges from the needlethread loop 4. This loop l6 extends transversely of the seam and islocked by the needle thread loop l0. There are additional looper threadsI! which are formed into loops I8 and these loops pass through thelooper thread loop 6, adjacent the needle loop l0, and extend across theseam and are locked by needle thread loops 3. The looper thread I1 iscarried by an additional looper movable longitudinally of the seam andclose to the middle needle. The loops l 6 and I8 lie diagonally in arectangle made by the needle stitches of two adjacent needles during thesewing operation. These diagonal loops and the loops of the first looperform a thorough coverage for the underface of the fabric which has notbeen obtained by any of the known seams. The seam shown in this Figureis highly elastic longitudinally of the seam and it is not elastictransversely'of the seam. A thorough coverage of the lower face of thefabric is obtained without appreciably increasing the thickness of theseam.

Figure 6 shows a four needle seam which includes a needle thread Iformed into loops 3 at one side of the seam and a needle thread 2 formedinto needle thread loops 4 at the other side of the seam. There are twoadditional needle threads [9 and 20 formed into needle thread loops 2|and 22 respectively. The needle thread loops form four parallel rows.This seam is particularly adapted for joining the abutted edges offabric. The edges will abut on a line midway between the rows of needlethread loops 2| and 22. The needle thread loops of each stitch formationare in alignment and a transverse looper carrying a looper thread 5forms a loop 6 which passes all of the needle thread groups just as inthe other forms of seams described above. The looper thread I is formedinto loops l6 and each loop [6 passes through a looper thread loop 6. Alooper thread loop l6 extends across to the row of needle loops 22 andis locked by one of said needle loops. There is a looper thread 23carried by a looper moving longitudinally of the seam and this looperthread is formed into loops 24. Each looper thread loop 24 passesthrough the looper thread loop 6 adjacent the needle thread loop 22 andextends across to the row of needle thread loops 2| and is locked by oneof said loops.

There is a third looper thread 25 which is formed into loops 26, Theseloops 26 pass through the looper thread loop 6 adjacent the needlethread loop 21 and extending across to the row of needle thread loops 3where it is locked by one of these needle thread loops. This seam hasthe characteristics as to elasticity in the direction longitudinally ofthe seam and non-elasticity transversely of the seam, the same as theseam shown in Figure 5. This four needle seam even forms greatercoverage for the underface of the fabric sections without increasing thethickness thereof.

Figure '7 shows a seam similar to that shown in Figure 1 except for themanner of securing or looking the second looper thread. The needlethread 2 is formed into loops 4 while needle thread I is formed intoloops 3. The opposed needle thread loops are locked by a looper thread 5formed into loops 6 which extend through both of the needle loops. Thelooper thread 21 is formed into loops 28.- These loops are passedthrough the looper thread loop 6 adjacent the needle loop 4 and then theloop is expanded and locked by passing about the needle loop 4 and theneedle loop 3 in the next stitch formation.

In Figure 8 there is shown a three needle seam similar to the seam shownin Figure '7. There is a needle thread i formed into needle loops 3 anda needle thread 2 formed into loops 4. There is an additional needlethread'29 formed into loops 30. The row of loops 30 are parallel withthe rows of needle thread loops 3 and 4 and lie midway between the same.A looper thread 5 is formed into thread loops 6 which are passed throughall three needle thread loops of a stitch formation. This looper threadloop 6 is locked by a looper thread 21 which passes through the looperthread loop 6 adjacent the needle 4 and is expanded and extends acrossthe seam and to the next stitch formation so that the loop is locked bythe needle loops 3, 3D and 4.

In Figure 4 of the drawings there is shown a covering thread. Such acovering thread could be used with any of the other forms of seams, andmore than one covering thread can also be used if desired.

It is noted that the characteristic feature of all of the seamsillustrated resides in the locking of the needle loops by a singlelooper thread loop which in turn is locked by a second looper threadloop and the second looper thread loop is locked by a needle loop orloops in the next stitch formation. This characteristic feature commonto all of the forms illustrated gives unusual elasticity to the scam ina longitudinal direction and at the same time a stitch formation isprovided Which is practically non-elastic in a transverse direction.

All of the new seams described provide an excellent coverage for thelower face of the fabric without unduly increasing the thickness of theseam. The seam is furthermore safe against raveling due to theparticular mutual locking of the needle threads and looper threads sothat the disadvantage of raveling on the breaking of a seam ispractically overcome.

All of the embodiments described have another advantage. Simple threadstrands extend along the edges of the lower side of the seam from stitchhole to stitch hole in the same way as on the top side of the seam. Onthe top side of the seam these strands are the needle threads lying atthe outside of the seam while at the lower side of the seam one strandof each of the looper thread 5 and the looper thread I extend along theoutside of the seam. Consequently, the lower side of the seam appears tobe very flat and narrow.

It is obvious that other arrangements of the concatenation of the needlethread loops and looper thread loops may be made without departing fromthe spirit of the invention as set forth in the appended claims.

I claim:

1. A flat seam for sewed articles comprising opposed fabric sections,stitching threads joining the fabric sections including, a plurality ofopposed needle thread loops penetrating the respective fabric sectionsin rows parallel with each other, a first looper thread passingtransversely of the fabric sections through all of the opposed needlethread loops on the underface of the fabric sections and a secondlooperthreadpassing through said first looper thread loop as *it emergesfrom a needle thread loop, said second looper thread loop extendingacross the fabric sections and locked by one of the succeeding needlethread loops.

2. A flat seam for sewed articles comprising opposed fabric sections,stitching threads joining the fabric sections including needle threadsextending along each edge of the fabric sections and formed into loopspenetrating the fabric sections, a looper thread extending along oneside of the fabric sections and formed into loops passing transverselyof the fabric sections through all of the opposed needle thread loopsand a second looper thread extending along the other side of the seamand formed into loops, each loop passing through the first-named looperthread loop as it emerges from the adjacent needle loop, said secondlooper thread loop extending across the fabric sections and locked byone of the succeeding needle thread loops at the other side of the seam.

3. A flat seam for sewed articles comprising fabric sections havingtheir edges abutted, a plurality of rows of needle thread loops, atleast one row being disposed at each side of the abutted edges andpenetrating the respective fabric sections, a single looper threadpassing transversely of the abutted edges through all of the opposedneedle thread loops anda second looper thread passing through said firstnamed looper thread loop as it emerges from a needle thread loop, saidsecond looper thread extending across the abutted edges and locked byone of the succeeding needle thread loops.

4. A flat seam for sewed articles comprising opposed fabric sections,stitching threads joining the fabric sections including three or moreneedle threads formed into loops and arranged in parallel rowspenetrating the fabric sections, a single looper thread passingtransversely of the fabric sections through all of the opposed needlethread loops, a second looper thread passing through the first looperthread loop as it emerges from a needle thread loop extending laterallyacross the fabric sections and locked by a succeeding needle thread loopin the next adjacent row, a third looper thread loop extending throughthe first named looper thread loop adjacent the needle loop in anintermediate row of needle thread loops, said third looper thread loopextending across the fabric sections and locked by one of the succeedingneedle thread loops in the next adjacent row of needle thread loops.

5. A flat seam for sewed articles comprising opposed fabric sections,stitching threads -joining the fabric sections including a plurality ofopposed needle thread loops penetrating the respective fabric sectionsin rows parallel with each other, a single looper thread passingtransversely of the fabric sections through all of the opposed needlethread loops, a second looper thread loop passing through the firstlooper thread loop as it emerges from a needle thread loop, said secondlooper thread loop being expanded and locked by all of the nextsucceeding needle thread loops.

FRIEDRICH LUTZ.

No references cited.

